An intensive effort was directed toward studying the preventive and therapeutic aspects of human immunodeficiency virus (HIV) infection and the acquired immunodeficiency syndrome (AIDS). A randomized trial comparing therapy with zidovudine (ZDV) versus interferon-alpha (IFN- alpha) versus the combination in 180 patients with early HIV-1 infection completed accrual and is currently active. A dose-tolerance study of the combination of IFN-alpha and dideoxyinosine (ddI) completed accrual of 53 patients and is now gathering long-term follow-up data. A randomized, double-blinded, placebo-controlled Phase II study of L-697,661 versus ZDV completed accrual of 84 patients. In this study, plasma viremia was found to be a reliable surrogate for anti-viral activity and the early development of resistance was noted using surrogate markers as efficacy parameters. A randomized, dose escalation study of U-90152S in combination with ZDV and ddI versus ZDV and ddI alone has enrolled 18 patients and continues to enroll. A dose-escalation study of PMEA has enrolled 12 patients and continues to enroll at the second dose level. Early results suggest that this agent has anti-retroviral activity in vivo. A phase I study of CD4-Pseudomonas Exotoxin (sCD4-PE40) in HIV- infected patients was initiated and enrolled 24 patients to determine the pharmacokinetics, maximally tolerated dose, and preliminary efficacy of this agent. Follow-up analysis of a randomized, controlled, masked trial of foscarnet in the treatment of cytomegalovirus retinitis in AIDS patients demonstrated an apparent survival benefit of this therapy.